I call attention to Berkeley’s treatment of a Newtonian indispensability argument against his own main position. I argue that the presence of this argument marks a significant moment in the history of philosophy and science: Newton’s achievements could serve as a separate and authoritative source of justification within philosophy. This marks the presence of a new kind of naturalism. A long the way, I argue against the claim tha t there is no explicit opposition or distinction between “philosophy” and “science” until the nineteenth century. Finally, I argue for the conceptual unity between Berkeley’s immaterialism and instrumentalism. I argue that Berkeley’s commitment to immaterialism requires his reinterpretation of science and, thus, the adoption of instrumentalism.